Underline argument in -Wnonnull and in C++ extend warning to the this pointer [PR...

Underline argument in -Wnonnull and in C++ extend warning to the this pointer [PR c++/86568].

Resolves:
PR c++/86568 - -Wnonnull warnings should highlight the relevant argument not the closing parenthesis

gcc/c-family/ChangeLog:

	PR c++/86568
	* c-common.c (struct nonnull_arg_ctx): Add members.
	(check_function_nonnull): Use nonnull_arg_ctx as argument.  Handle
	C++ member functions specially.  Consider the this pointer implicitly
	nonnull.
	(check_nonnull_arg): Use location of argument when available.
	(check_function_arguments): Use nonnull_arg_ctx as argument.

gcc/ChangeLog:

	PR c++/86568
	* calls.c (maybe_warn_rdwr_sizes): Use location of argument if
	available.
	* tree-ssa-ccp.c (pass_post_ipa_warn::execute): Same.  Adjust
	indentation.
	* tree.c (get_nonnull_args): Consider the this pointer implicitly
	nonnull.
	* var-tracking.c (deps_vec): New type.
	(var_loc_dep_vec): New function.
	(VAR_LOC_DEP_VEC): Use it.

gcc/testsuite/ChangeLog:

	PR c++/86568
	* g++.dg/warn/Wnonnull5.C: New test.
	* c-c++-common/pr28656.c: Adjust text of expected warning.
	* c-c++-common/pr66208.c: Same.
	* g++.dg/cpp0x/nullptr22.C: Same.
	* g++.dg/ext/attr-nonnull.C: Same.
	* g++.dg/ext/attrib49.C: Same.
	* g++.dg/pr71973-2.C: Same.
	* g++.dg/warn/Wnonnull3.C: Same.
	* g++.dg/warn/Wnonnull4.C: Same.
	* obj-c++.dg/attributes/method-nonnull-1.mm: Same.
	* objc.dg/attributes/method-nonnull-1.m: Same.